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How To List Files in a Folder Using Bash Scripting

Ubuntu 12

Bash scripting is a powerful tool that can automate tasks, manage files, and perform complex operations. In this article, we’ll focus on how to list files in a folder using bash scripting. We’ll cover various scenarios, such as listing all files, files with a specific extension, and files in subfolders.

Quick Answer

To list files in a folder using bash scripting, you can use the ls command followed by the folder path to list all files, or add a specific file extension to list files with that extension. If you want to list files in subfolders, you can use the find command with the folder path and the -type f option. Additionally, you can create a bash script to change the directory and list files using a loop.

Understanding Bash Scripting

Bash (Bourne Again Shell) is a shell program on Unix and Linux systems. It allows you to interact with the system using text-based commands and scripts. Bash scripting is writing a series of commands in a file to be executed by the Bash shell.

Basic Command: Listing All Files

The simplest way to list all files in a folder is using the ls command. Here’s how you do it:

ls /path/to/folder

In this command, ls is a command-line utility for listing directory contents in Unix and Unix-like operating systems. /path/to/folder is the directory path where you want to list the files. Replace this with your actual folder path.

Listing Files with Specific Extension

If you want to list only files with a specific extension, you can do so by adding the extension to the ls command:

ls /path/to/folder/*.extension

Replace extension with the file extension you’re interested in (e.g., txt, jpg, etc.). This command will list only files with the specified extension in the folder.

Listing Files in Subfolders

To list files in the subfolders of a directory, you can use the find command:

find /path/to/folder -type f

Here, find is a command-line utility that searches and locates the list of files and directories based on conditions you specify for files that match the arguments. /path/to/folder is the directory path where you want to list the files. -type f is an option that instructs find to search for files only, not directories.

Bash Script to Change Directory and List Files

If you want to change the directory and list the files, you can use the following bash script:

#!/bin/bash

folder="/home/user012/Desktop/folder2Start"

cd "$folder" || exit 1

for dir in */; do
 echo "$dir"
done

This script starts with #!/bin/bash, which is a shebang line that tells the system this is a bash script.

The folder variable is set to the desired folder path. The cd command changes the directory to that folder. If the cd command fails (e.g., if the folder doesn’t exist), the script exits with an error code using exit 1.

The for loop iterates over each subdirectory in the folder (*/ matches only directories). The echo command then prints the name of each subdirectory, effectively listing the folders.

Remember to make the script executable using the chmod +x script.sh command and run it using ./script.sh.

Conclusion

Bash scripting provides a powerful way to interact with files and directories. By understanding the ls and find commands, you can easily list files in a folder and perform more complex operations. Practice these commands and scripts, and you’ll become proficient at managing files with bash scripting. For more information on bash scripting, check out the GNU Bash Documentation.

What is the difference between Bash and Shell scripting?

Bash is a specific type of shell program, known as the Bourne Again Shell, while shell scripting refers to the practice of writing scripts using any shell program. Bash is one of the most commonly used shell programs on Unix and Linux systems.

How do I check if a file exists in a bash script?

You can use the test command or its equivalent [ to check if a file exists. Here’s an example:

if [ -f /path/to/file ]; then
 echo "File exists!"
else
 echo "File does not exist."
fi

In this example, -f checks if the given path is a regular file. You can replace /path/to/file with the actual path to the file you want to check.

Can I list files in a folder and its subfolders at the same time?

Yes, you can use the find command to list files in a folder and its subfolders. Here’s an example:

find /path/to/folder -type f

This command will list all files (-type f) in the specified folder and its subfolders.

How can I sort the listed files by their modification time?

You can use the ls command with the -lt option to list files in descending order of modification time. Here’s an example:

ls -lt /path/to/folder

This command will list files in /path/to/folder and its subfolders, sorted by modification time in descending order.

How can I list only the names of files without any additional information?

You can use the -1 (dash one) option with the ls command to list only the names of files, one per line. Here’s an example:

ls -1 /path/to/folder

This command will list only the names of files in /path/to/folder and its subfolders, with each file name on a separate line.

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